A variety of tilting and telescope traveling steering column arrangements have been developed in the field of automotive vehicles. In such a tilting and telescope traveling steering column arrangement, the telescope traveling mechanism is usually arranged as follows: a part of a steering shaft on which a steering wheel is mounted is axially slidably fitted in a fixed tube fastened to a movable bracket, in which the splines of the part of the steering shaft are in engagement with the splines of the fixed tube. This allows the steering shaft to axially move relative to the fixed tube. The steering shaft is coaxially fitted with a telescopic upper jacket which is coaxially fitted in a telescopic lower jacket fixed to the movable bracket. The telescopic upper jacket is formed with a threaded portion which is engaged with a threaded portion of a telescopic sleeve. The telescopic sleeve is rotated around its axis by an electric motor, thus axially displacing the steering shaft.
However, telescope motions of the steering shaft are accomplished under engagement of external and internal threads, in which the external and internal threads displace axially relative to each other upon rotation. Since such engagement of the external and internal threads are considerably high in frictional resistance, a relatively large force is required to axially displace the steering shaft. Accordingly, the electric motor is required to have a high output capacity and therefore becomes high in cost. As a result, an electrically operated telescope traveling mechanism is costly and difficult to implement.
Tilting functions are also commonplace. Many configurations are available in the prior art for steering column tilt mechanisms. However, many of the prior art systems are cumbersome and bulky, thus resulting in packaging and cost problems. Also, these designs do not easily lend themselves to steering column collapse designs for a vehicle crash situation. Some common collapsible steering column shaft assemblies are disclosed in U.S. Pat. Nos. 3,492,888, 3,656,366, and 4,183,258.
Another important steering column design consideration is to provide for energy absorption at impact in the steering column. One such energy absorption means is provided by the absorption bracket disclosed in U.S. Pat. No. 3,600,971. However, this energy absorbing bracket does not allow the steering column assembly to collapse upon itself, nor is it functional with a tilt or telescope arrangement.
It would be desirable to provide a tilting and telescoping steering column assembly which has energy absorption means, and is internally collapsible.
It would be further desirable to provide a tilting and telescoping assembly with position sensors to provide means for memory of desired steering wheel positions for different drivers.